Home/Contractor Resource Center/Workers’ Compensation
13 min read Updated August 2026 Reviewed by Unique Risk Management
Workers’ compensation covers medical costs and lost wages when an employee is injured or becomes ill on the job. In exchange, employees generally give up the right to sue their employer over the injury, a trade-off that protects both sides.
For contractors specifically, it’s also one of the most heavily scrutinized coverages on a job: general contractors, developers, and public agencies routinely check it before you’re even allowed to bid.
In California, any business with one or more employees is generally required to carry workers’ compensation, with narrow exemptions for qualifying owners. Requirements vary by state, we’re licensed in California, Florida, Minnesota, Utah, and New Jersey, and can walk you through what applies where you operate.
Everything upstream of your X-Mod, payroll and manual rates, is largely outside your control. The formula itself is simple; the inputs are where the real work happens.
Premium = (Payroll ÷ 100) × Manual Rate × X-Mod
Every contractor starts at a baseline of 1.00. Below that is a "credit mod", your losses run better than average for your class of work, and you pay less. Above 1.00 is a "debit mod", your losses run worse, and you pay more.
The formula splits every claim into a heavily-weighted "primary" portion and a lightly-weighted "excess" portion, which is why claim frequency moves your mod more than the size of any one claim. Three small soft-tissue claims will typically hurt your mod more than one unusually large one.
Our complete whitepaper on how the formula works, how claims age off your record, and how to protect your mod at renewal.
To make the stakes concrete, here’s the same contractor under two different claims histories:
Manual Premium$220,000
X-Mod0.85
Premium After Mod$187,000
vs. a 1.00 mod$33,000 saved
Manual Premium$220,000
X-Mod1.35
Premium After Mod$297,000
vs. a 1.00 mod$77,000 added
Each claim typically factors into your mod for three consecutive rating years before rolling off, regardless of when it closes.
Yes. If a claim was miscoded or the worksheet contains an error, your broker can request a correction from the rating bureau, this is routine, not a formal dispute.
It follows you, not the carrier. Your mod is calculated by the rating bureau from your claims history, independent of who underwrites the policy.
No, it applies specifically to workers’ compensation. That said, a poor safety record often shows up across other coverage lines too.
The deep-dive companion to this page’s flagship section.
A closer look at primary vs. excess losses and the ballast value.
Practical setup for contractors who don’t have one yet.
What a "good" mod actually looks like for roofers, electricians, and GCs.
Request a free Workers’ Compensation Scorecard, or download the complete X-Mod whitepaper first.